Not applicable.
Not applicable.
I. Field of the Invention
This invention relates generally to ammunition and explosives and, more particularly, to an incendiary munition projectile which is particularly well adapted for use in destroying large nominally explosive targets, but which is also advantageously usable for other ordinance applications. Projectiles of the present invention are Well adapted to be fired from relatively small caliber, rapid fire guns in the 20 mm to 40 mm class. Construction is accomplished by benign incineration utilizing a tracer ignited, pyrogenically activated intermetallic reactive payload in a conventional projectile.
II. Related Art
Pyrogenically activated compositions are commonly utilized in military ammunition to produce visible or tracer rounds which have long been included in multiple round firing guns as every nTH round to produce a serial spaced sequential representation of the trajectory or path of each tracer projectile which is visible to the operator of the weapon to permit the operator or an observer to observe and follow the path of each tracer projectile and follow the round between launch from the firing piece and the intended target. The percentage of tracer rounds and the total number of rounds can vary from a relatively high to a relatively low percentage depending on the application and such ace included in almost every rapid fire armament ammunition.
As is the case with many other pyrotechnic compositions, tracer compositions are basically a mixture of an oxidizing agent and a metallic fuel often utilized in conjunction with other materials added to the mixture to modify the burning rate, visual effect and to increase handling safety. Typical metallic fuel materials include magnesium and aluminum and typical oxidizing materials include strontium nitrate. These compositions are normally held together with a binder material which may also act as a color intensifier if it contains chlorine or fluorine, a water proofing agent and/or a flame retardant material.
The tracer material is designed to be ignited by the projectile propellant and thereafter maintain a sufficiently intense visible lumination such that the projectile flight can be followed to the target. In most cases, the tracer has no discrete ignition effect on the target at all, but may, on occasion, ignite fires in fossil fuels or the like.
Many large explosive-containing targets exist that need to be safely destroyed as by deflagration or detonation from a safe distance. These include mines, torpedo warheads or unexploded bombs, or the like, which may come within range of relatively small caliber guns in the 20 MM-40 MM range. It would be a great advantage if such weapons could be used unmodified to destroy such targets, i.e., with no more preparation time than is needed to aim the gun at the target. Thus, there exists a need for a standardized projectile round which can be fired by such a gun, unmodified and that will destroy certain large explosive targets which are difficult or impossible to destroy safely with conventional rounds. In addition, it would be desirable if such projectile could accomplish destruction of such large explosive targets generally without detonation of the explosives contained in the targets.
Accordingly, in view of the above, it is a primary object of the present invention to provide a projectile for the destruction of large, nominally explosive targets which can be fired from a conventional, unmodified weapon. Another object of the present invention is to provide a projectile for the destruction of large explosive targets which infuses heat into the explosive material to achieve deflagration.
A further object of the present invention is to provide a projectile for the destruction of large explosive targets which utilizes a pyrogenically activated intermetallic payload to produce a temperature in the range necessary to destroy the explosive material by deflagration.
A still further object of the present invention is to provide a projectile for the destruction of large explosive targets utilizing a pyrogenically activated intermetallic reactive payload which is ignited post launch by an amount of tracer material in the projectile.
A yet still further object of the present invention is to provide a projectile for the destruction of large explosive targets which utilizes an intermetallic reactive payload selected bi-metallic constituent systems selected from titanium and boron and nickel and aluminum.
Other objects and advantages will occur to those skilled in the art upon familiarization with the descriptions and accounts contained in the specification, drawing s and claims of the application.
In the means of the present invention, there is provided a projectile for the destruction of large, nominally explosive targets which is of conventional size and weight such that it can be fired along with other ammunition from the conventional, unmodified gun system. The projectile concept of the invention allows the delivery of a high temperature (2000xc2x0 C. or more) payload at long standoffs to accomplish the destruction via deflagration or detonation at a safe distance. The system can be used on large targets such as mines, torpedo warheads or unexploded bombs. The projectile concept of the invention utilizes launch propellant to initiate tracer material which, in turn, ignites the payload post launch. The nose of the projectile can be equipped with a conventional or a high intrusion penetrator system in the forward nose section as preferably configures to have conventional ballistics with respect to a typical round utilized in the gun of interest.
The projectile of the invention includes a generally hollow conventional projectile shell body having a tapered forward nose section and an aft section with the nose section being filled with a pyrogenically activated intermetallic reactive (IMR) payload in the forward section. An amount of tracer igniter material is loaded behind the intermetallic reactive material payload and in contact with it. Upon firing, the tracer is ignited by the shell propellant in a conventional manner and it, in turn, ignites the intermetallic reactive material payload after a pre-determined reacting time to allow safe separation from the launching platform prior to payload ignition. The heat from the tracer compound starts the reaction in the intermetallic reactive payload. The payload forms a new solid at a very high temperature (2000xc2x0 C. or more) before the projectile strikes the target. Upon impact, the projectile breaks up in a controlled fashion, distributing hot fragments throughout the high explosive target causing deflagration. In this manner, an extremely hat wave front is propagated in the target which subsequently ignites on impact. If desired, a penetrator nose can be used in the shell to increase projectile intrusion.
With respect to the payload itself, the preferred material for the intermetallic reactive payload is a bimetallic reactive material selected from titanium and boron, which produce titanium boride (TiB) and nickel and aluminum which produce nickel aluminide (NiAl). The tracer material may be any standard tracer compound combination available, such as magnesium and strontium nitrate, and used for ammunition of the class of interest and no special tracer material need be employed. If necessary, binders such as Polytetrafluoroethylene (PTFE) or other materials to modify the reaction rats or progression can be put in the material as additives. The ballistics of the projectiles of the invention are generally conventional, although small amounts of gaseous bi-product given off by the high temperature reaction may cause some additional drag effects which may be otherwise compensated for in the construction of the cartridge or the propellant load.